Goldman Sachs forecasts low long-term S&P 500 returns (3-6.5% annually). The key reason is that today's high market concentration implies higher future volatility, yet investors aren't being compensated for this risk because current valuations are already historically high and likely to contract.

Contrary to popular belief, earnings growth has a very low correlation with decadal stock returns. The primary driver is the change in the valuation multiple (e.g., P/E ratio expansion or contraction). The correlation between 10-year real returns and 10-year valuation changes is a staggering 0.9, while it is tiny for earnings growth.

Despite the confidence with which they are presented, annual stock market predictions from major investment banks are notoriously unreliable. Data from 2003-2023 shows the median forecast was off by 14 percentage points, highlighting the futility of trying to precisely time the market based on expert commentary.

The asymmetrical nature of stock returns, driven by power laws, means a handful of massive winners can more than compensate for numerous losers, even if half your investments fail. This is due to convex compounding, where upside is unlimited but downside is capped at 100%.

An average stock's return is dictated more by external forces than company performance: 40% by the market and 30% by its sector, with only 30% attributable to idiosyncratic factors. This means correctly identifying a winning sector is nearly as valuable as picking the best stock within it.

Contrary to the belief that only a few mega-cap stocks drive market returns, a significant portion of S&P 500 companies—167 in the year of recording—outperform the index. This suggests that beating the market through stock picking is more attainable than commonly portrayed.

Investors often expect an average 8-10% annual return from stocks. However, historical data shows the most common yearly outcomes are monster returns of +15-20%, with +20-35% returns also being frequent. This demonstrates that market performance is characterized by periods of extreme gains, not steady, average growth, a concept investor Ken Fisher termed "normal market returns are extreme."

Media headlines of 10% stock market returns are misleading. After accounting for inflation, fees, and taxes, the actual purchasing power an investor gains is far lower. Using real returns provides a sober and more accurate basis for financial planning.

Timing is more critical than talent. An investor who beat the market by 5% annually from 1960-1980 made less than an investor who underperformed by 5% from 1980-2000. This illustrates how the macro environment and the starting point of an investment journey can have a far greater impact on absolute returns than individual stock-picking skill.